Made available in DSpace on 2014-06-11T19:27:26Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-04-29Bitstream added on 2014-06-13T20:16:46Z : No. of bitstreams: 1 rissi_mn_me_botib.pdf: 4013269 bytes, checksum: 7f2b7759ec50422f03c785156a434e65 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / The concepts degraded environment and disturbed environment were initially proposed based on the observation of such processes in forest fragments. Disturbed environments, when subjected to agents, can reestablish after the removal of the disturbing factor. However, when the action is more intense and there is no potential to return to conditions similar to the previous ones, the vegetation is considered degraded. The question is: Would the actions that make a forest degraded have the same consequence in cerrado fragments? The present study aims to analyze the composition of the regenerative community over one year in a cerrado fragment located in the Municipal Botanical Garden of Bauru City, São Paulo State, Brazil (JBMB); to provide data to understand the ecological processes involved in the natural regeneration of degraded cerrado areas and the chemical combat as a viable alternative or not to control alien plants; and to contribute to the knowledge of the cerrado flora in Bauru region. Thus, some questions were raised. How does natural regeneration of the woody vegetation of a degraded cerrado occur? Would the chemical combat against invasive alien plants change the development of cerrado plants? Is intervention in the control of those plants favorable? The study area was deforested by the action of settlers, who established there in 1997. In 2007 the area was endorsed to the Municipal Botanical Garden of Bauru City (JBMB). During this period, the native vegetation was substituted for pasture. By two years ago the place has been abandoned and the natural vegetation started to regenerate. To evaluate the natural regeneration potential of cerrado, a comparative floristic and phytosociological survey was carried out in three areas inside JBMB. The first area is inserted in a cerradão fragment, free of... (Complete abstract click electronic access below)

abstract: Mycorrhizal fungi form symbiotic relationships with plant roots, increasing nutrient and water availability to plants and improving soil stability. Mechanical disturbance of soil has been found to reduce mycorrhizal inoculum in soils, but findings have been inconsistent. To examine the impact of restoration practices on riparian mycorrhizal inoculum potential, soil samples were collected at the Tres Rios Ecosystem Restoration and Flood Control Project located at the confluence of the Salt, Gila, and Agua Fria rivers in central Arizona. The project involved the mechanical removal of invasive Tamarix spp.( tamarisk, salt cedar) and grading prior to revegetation. Soil samples were collected from three stages of restoration: pre-restoration, soil banks with chipped vegetation, and in areas that had been graded in preparation for revegetation. Bioassay plants were grown in the soil samples and roots analyzed for arbuscular mycorrhizal (AM) and ectomycorrhizal (EM) infection percentages. Vegetations measurements were also taken for woody vegetation at the site. The mean number of AM and EM fungal propagules did not differ between the three treatment area, but inoculum levels did differ between AM and EM fungi with AM fungal propagules detected at moderate levels and EM fungi at very low levels. These differences may have been related to availability of host plants since AM fungi form associations with a variety of desert riparian forbs and grasses and EM fungi only form associations with Populus spp. and Salix spp. which were present at the site but at low density and canopy cover. Prior studies have also found that EM fungi may be more affected by tamarisk invasions than AM fungi. Our results were similar to other restoration projects for AM fungi suggesting that it may not be necessary to add AM fungi to soil prior to planting native vegetation because of the moderate presence of AM fungi even in soils dominated by tamarisk and exposed to soil disturbance during the restoration process. In contrast when planting trees that form EM associations, it may be beneficial to augment soil with EM fungi collected from riparian areas or to pre-inoculate plants prior to planting. / Dissertation/Thesis / M.S. Applied Biological Sciences 2012

Wildfires play a significant role in many different elements of Mediterranean forest ecosystems. In recent years, prescribed fires have started being used more often as a fuel reduction tool, and also as silvicultural treatment to help the regeneration and health improvement of stands. Apart from the fact that fire may alter microsite conditions, very little is known about the impact of prescribed burning on natural regeneration or plant species renewal in Mediterranean pine forests. Likewise, knowledge about the influence of seedling predators on post-fire regeneration is still scarce. In this study, we aimed to compare the effects of seedling predation on recruitment in earlier stages after prescribed burnings in three pine stands in Central Spain: a pure stand of Pinus nigra; a mixed stand of Pinus halepensis and Pinus pinaster and a mixed stand P. nigra with P. pinaster. In situ we superficially sowed seeds from two different species. In the sowing experiment, we tested two different seed provenances (drier and more humid spanish regions) for each species. In all, 60 plots (30 burned, 30 unburned) per site, with 10 seeding units per plot and more than 20,000 seeds, were used in the whole study. Seedling predation was evaluated by replicating the seeding units inside and outside a wire cage as protection for rodents and birds. Our results showed that prescribed fires alter initial seedling predation intensity: predation was significantly higher in the seedlings grown in the plots affected by prescribed fire. The individuals sown before the fire passed showed slightly more predation than those sown after fire passage. Provenances did not appear as an important predation drive. Understanding the role of the predation associated with these treatments can help improve Mediterranean pine forest management.

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In 2017 the Kenow wildfire burned thirty-eight percent of Waterton Lakes National Park (WLNP) in southern Alberta at high to very high severity in mere hours. The ecological impacts of the fire will have implications for resource management, including the practice of ecological restoration, for decades to come. In this thesis I ask two main questions. First, in what ways are people who are involved in managing WLNP’s ecosystems experiencing the effects of the Kenow wildfire, and how does their experience combined with the severity and extent of the Kenow wildfire influence park management and ecological restoration approaches in WLNP? Subsidiary to this, I ask, what is the role of history, and the role of future climate projections in managing the post-fire landscape? This research is part of the larger Mountain Legacy Project (MLP), which is systematically repeating historic survey photographs taken in the early 1900s across Canada’s mountain landscapes. I use third-view photographs in photo-elicited semi-structured interviews with park staff to answer my first question. In my second research question I ask what broader themes and specific issues do third-view repeat mountain photographs elicit about ecological restoration and park management. As a follow up, I inquire into what ways photo-elicitation functions as an effective method in park management research? Fourteen participants were interviewed, the majority were resource conservation staff, in addition to one retired park warden, a member of the cultural resources unit, a communications staff, and a former staff member. Participants felt wide-ranging emotions relating to the Kenow fire including grief over loss, happiness about regrowth, excitement about learning, anxiety about people’s safety, and stress over increased workloads. Park management frames vegetation regeneration after the Kenow fire as renewal, accepting that the landscape may look different than it did before the fire. Climate change is only beginning to be integrated into ecological restoration, though park management is adapting to climate change by encouraging renewal under a new climate. Historical knowledge still guides decision making in several ways. Major restoration projects including invasive species management, whitebark and limber pine restoration, and prescribed burning, were all impacted by the Kenow fire. Participants shared their thoughts on unconventional approaches such as novel ecosystems, highlighting misunderstandings and misapprehensions about the concept. Parks Canada has an opportunity to learn from Waterton Lakes’ experience to help streamline their post-emergency response in the future. Findings relating to my second question show these themes and issues were discussed most often by participants when looking at the third-view mountain photographs: fire behaviour, regeneration/renewal, and ecological impacts of the Kenow fire; encroachment; prescribed burning; personal narratives; ecological effects of climate change; and other snapshots. Just less than half the participants did not engage significantly with the photos, which highlights a challenge in using researcher chosen photos. However, many participants did engage and had much to say about the photos, including sharing memories and personal stories. Pre-determined interview questions were essential in unearthing the findings in this thesis, as the photos did not elicit this information alone. / Graduate

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Since the 1970s, the institution of fire management has been in a frustrated transition from fire suppression and control to ecologically informed fire management. Administrative boundaries, professional specializations and organizational incentives and funding mechanisms have stalled the adoption of landscape scale ecological fire restoration as a guiding paradigm. Using a case study approach, this dissertation examines the potential of a multi-scalar collaborative network, the US Fire Learning Network (FLN), to catalyze the changes necessary to overcome the frustrated transition. Established in 2002 in an agreement between the USDA Forest Service, The Nature Conservancy, and the US Department of Interior, the FLN operates at landscape, regional and national scales. In this multi-scalar context, the network utilizes planning technologies, communication modalities, and interpersonal interaction to link participants at each scale and motivate them to enhance their collaborative ecological restoration planning capacities. The network directly addresses the challenges of the frustrated transition by enabling practitioners to collaborate across administrative and disciplinary boundaries, develop expertise in ecological fire restoration planning and management, and to inform policy changes at the federal level that can create new incentives and funding mechanisms that support landscape scale ecological restoration. While institutional transformation has yet to occur, the FLN sets the stage to address the core challenges that fire management practitioners and organizations face as they engage in landscape scale ecological fire restoration. This work provides theoretical and practical insights to collaborative planning research by introducing new forms of collaborative practice, describing how collaborative planning can be conducted across multiple scales simultaneously, and establishing how multi-scalar collaborative networks may be able to catalyze institutional change necessary to respond to complex cross scalar environmental problems. / Ph. D.

Joint-head grass (Arthraxon hispidus) is a widespread nonindigenous plant species in the eastern United States. It is observed forming large monodominant patches that impact native and managed grassland systems. With such little understanding of its foundational biology or ecological impacts, leaving land managers desperate for effective control measures to manage A. hispidus invasion. We conducted a series of complementary experiments on six populations of A. hispidus to better understand how environmental factors affect seed germination. Germination is a critical life stage that allows a species to disperse. Freshly harvested seeds germinated effectively within 14 days of imbibition in the dark at 23°C, exhibiting little to no dormancy or influence by light. A pH range of 5 - 10 resulted in ≥ 80% germination, suggesting that pH will not limit colonization in other portions of the United States. Arthaxon hispidus was tolerant to abiotic stressors such as salinity and osmotic potential. The concentration required to limit germination to 50% (LD50) in the populations tested surpassed soil salinity found in the contiguous United States and some tidal systems (Frederick, MD = 354; Lincoln, MO = 354; Williamsburg, VA = 298 mM NaCl). While drought adversely affects A. hispidus germination, the LD50 occurred in moderate to more severe osmotic potentials (Frederick, MD = -0.67; Lincoln, MO = -0.37; Williamsburg, VA = -0.25 MPa) making A. hispidus expansion more likely in wetter years and regions. Constant temperature treatments resulted in germination percentages across a range of temperatures (8 - 37°C), and A. hispidus is well distributed in several major temperature regimes found in the United States. Finally, emergence greatly decreased with burial depth. Emergence occurred at ≥ 43% at 1 - 2 cm, decreasing to 5% at 6 cm, and 0% at 8-cm depths. With adequate soil moisture, a broad range of germination temperatures, and a decreased emergence rate with depth, we believe A. hispidus is unlikely to develop a seed bank. These initial studies on A. hispidus' germination posit a broad range of environmental tolerances; although, it may be limited by other life stages. / Master of Science / Joint-head grass is a non-native invasive plant species commonly found in the eastern United States. It is observed growing in large patches that negatively affect the environment. These effects can include decreasing biodiversity or lowering forage availability which negatively can impact cattle production. To better understand the basic biology of joint-head grass, we decided to harvest seeds to study from several populations in the United States. We tested differences in the populations by examining the different environmental effects on joint-head grass germination. Germination is a critical life stage of invasive plants; therefore, we developed complementary experiments to test the effects of the environment on seed germination. We've determined that germination occurs effectively under the effect of several environmental stressors. Germination occurred under salty (NaCl) conditions which may allow it to establish in tidal systems where brackish water is present. We've also determined that germination occurs effectively ( ≥ 80%) at a pH range from 5 - 10. This will allow joint-head grass to germinate in more basic soils commonly found in the western part of the United States. Further, we tested the moisture requirements for germination to occur, and we've found that it is tolerant to moderate to more severe drought conditions. Joint-head grass is also capable of germinating across a range of temperatures (8-37°C). The United States has well-distributed rainfall and suitable temperatures in large portions of the country. We believe the climate of the United States is well-suited for joint-head grass establishment, and that it may spread more frequently in years with higher precipitation during the growing season. This species potentially poses a threat to both our natural and agricultural systems.

A direct consequence of disorganized human population growth and the indiscriminate use of natural resources are the reduction of area and the fragmentation of native ecosystems, as they transform into agricultural areas. In this scenario, agroforestry systems (AFS) may be an alternative to reconcile restoration, conservation and local agricultural production. However, there is a diversity of AFS, and its use as a forest restoration strategy is still uncertain, mainly because we lack evaluations based on ecological indicators from those systems. Thus, we compared ecological indicators measured in a coffee agroforestry system in the Pontal do Paranapanema with those inform conventional restoration plantings of the same age and with regional reference ecosystems. We measured natural regeneration density and richness; canopy cover by native species and aboveground biomass and compared among sites using an ANOVA, followed by Tukey\'s test for mean comparison. Aiming to understand the factors influencing the ecological indicators of forest restoration in coffee AFS, we performed generalized linear models (GLM) using density of coffee and native trees, biomass, percentage of animal-dispersed trees, distance to the nearest forest remnant and richness of tree species as predictor variables and percentage of canopy cover and density and richness of natural regeneration as response variables. The reference forests had the highest values for forest structure indicators, followed by AFS and finally by the conventional restoration plantings. However, we found a greater diversity of tree species planted in the AFS and a natural regeneration similar to that found in the reference ecosystems. Despite coffee density in the AFS negatively influencing natural regeneration, the coffee AFS had greater ecological performance than the conventional restoration, being a viable alternative for forest restoration. We conclude that AFS with coffee and native tree species play an important ecological role in the FLR in Pontal do Paranapanema, reconciling productivity with forest restoration. / Um reflexo direto do crescimento desordenado da população humana e das atividades antrópicas é a diminuição e a fragmentação da área ocupada por ecossistemas nativos e sua substituição por áreas agrícolas. Neste cenário, os sistemas agroflorestais (SAF) podem ser uma alternativa para conciliar restauração, conservação e produção agrícola local. No entanto, tendo em vista a diversidade de SAFs, sua adoção como estratégia de restauração florestal ainda carece de estudos que avaliem os níveis de indicadores ecológicos de cada sistema. Neste sentido, comparamos os indicadores ecológicos de sistemas agroflorestais com café e espécies arbóreas nativas no Pontal do Paranapanema, com os de plantios convencionais de restauração florestal de mesma idade (12-15 anos) e ecossistemas de referência regionais. Medimos a densidade e a riqueza da regeneração natural, a cobertura do solo por espécies nativas e a biomassa acima do solo e as comparamos entre as áreas pela análise de variância ANOVA seguida da comparação de médias pelo teste de Tukey. Buscando compreender os fatores que influenciam os indicadores ecológicos da restauração florestal no SAF, analisamos modelos lineares generalizados, tendo biomassa, porcentagem de árvores zoocóricas, distância do remanescente florestal mais próximo, densidades de café, riqueza e densidade de árvores nativas como variáveis preditoras, e porcentagem de cobertura do dossel, densidade e riqueza da regeneração natural como variáveis respostas. As florestas de referência tiveram os maiores valores para indicadores de estrutura florestal, seguidas pelos SAFs e pelos plantios convencionais de restauração florestal. Entretanto, encontramos elevada diversidade de espécies arbóreas nos SAFs e valores próximos aos das florestas de referência para a diversidade da regeneração natural. Embora a densidade de plantas de café influencie negativamente a regeneração natural, os SAFs apresentaram um melhor desempenho ecológico que as áreas de restauração convencional, correspondendo à uma alternativa viável para restauração florestal. Desta forma, concluímos que os sistemas agroflorestais estudados desempenham um papel ecológico importante na restauração da paisagem florestal no Pontal do Paranapanema, conciliando produção com restauração florestal.

Master of Science / Division of Biology / John M. Blair / Temperate grasslands are among the most threatened biomes in the world, with the largest historical losses due to conversion to agricultural land. While much of this biome has already been converted, there is concern the last remaining remnants in North America will be converted in response to increasing demand for crops used for ethanol production. Thus, restoring grasslands post-anthropogenic disturbance is increasingly important for conserving grassland biodiversity. Two major challenges for prairie restorations are establishing the many subdominant and rarer species found in native prairie, and offsetting the typical decline in richness and diversity over time as restorations age. Repeated seed addition of targeted species is commonly used to override low and declining plant richness and diversity. While this is generally effective early in restoration (i.e., as communities are establishing), its effectiveness in later stages (i.e., when established communities are often losing diversity) remains unknown. I investigated plant community responses to combinations of resource manipulations and disturbances coupled with a seed addition in a 15-yr old restored grassland to test the hypothesis that spatial resource heterogeneity increases the rate of colonization into established prairie restoration communities. Seeds were added to a long-term restoration experiment involving soil depth manipulations (deep, shallow) crossed with nutrient manipulations (reduced N, ambient N, enriched N). Seedling emergence was generally low and only 8 of the 14 forb species added were detected in the first growing season. I found no effect of increased resource heterogeneity on the abundance or richness of seedlings. There was a significant nutrient effect (p<0.1, α=0.1) on seedling abundance, with higher emergence in the enriched N than the ambient N treatment. I also found unexpected nutrient effects on richness, diversity and Mean C (Mean C = Σ CoCi*Ai, where CoC=Coefficient of Conservatism and A=relative abundance of the ith species). All values, except Mean C, were higher in the enriched N treatment than in either the reduced or ambient N treatments. Mean C was lowest in the enriched N treatment, and highest in the whole-plot control, suggesting that the majority of species contributing to higher richness and diversity in the enriched N treatment were “weedier” species. In a separate experiment, I found no effect of small-scale disturbances (aboveground biomass removal or soil disturbance) on seedling abundance or seedling richness. I did find a marginal effect of disturbance type on seedling richness (p=0.11, α=0.1), with higher seedling richness in the soil disturbance than the aboveground biomass removal treatment. I did not find any disturbance effects on community response variables. These results indicate that recruitment from seed additions into well-established restored communities is relatively low in the first year following a seed addition, regardless of resource availability and heterogeneity. Follow-up studies to determine recruitment rates in subsequent years are needed to elucidate whether recruitment responses are driven more by individual species differences or by environmental mechanisms.